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Kappa (/ˈkæpə/;[1] uppercase Κ, lowercase κ or cursive ϰ; Greek: κάππα, káppa) is the tenth letter of the Greek alphabet, representing the voiceless velar plosive IPA: [k] sound in Ancient and Modern Greek. In the system of Greek numerals, Kʹ has a value of 20. It was derived from the Phoenician letter kaph . Letters that arose from kappa include the Roman K and Cyrillic К. The uppercase form is identical to the Latin K.
![](http://178.128.105.246/content-http-upload.wikimedia.org/wikipedia/commons/thumb/9/9c/Greek_lowercase_kappa_variant.svg/75px-Greek_lowercase_kappa_variant.svg.png)
![](http://178.128.105.246/content-http-upload.wikimedia.org/wikipedia/commons/thumb/3/3d/Greek_word_%CE%BA%CE%B1%CE%AF_written_with_a_handwritten_variant_of_kappa%2C_from_the_Byzantine_period.png/220px-Greek_word_%CE%BA%CE%B1%CE%AF_written_with_a_handwritten_variant_of_kappa%2C_from_the_Byzantine_period.png)
Greek proper names and placenames containing kappa are often written in English with "c" due to the Romans' transliterations into the Latin alphabet: Constantinople, Corinth, Crete. All formal modern romanizations of Greek now use the letter "k", however.[citation needed]
The cursive form ϰ is generally a simple font variant of lower-case kappa, but it is encoded separately in Unicode for occasions where it is used as a separate symbol in math and science. In mathematics, the kappa curve is named after this letter; the tangents of this curve were first calculated by Isaac Barrow in the 17th century.
Symbol
editLowercase (κ)
edit- Mathematics and statistics
- In graph theory, the connectivity of a graph is given by κ.
- In differential geometry, the curvature of a curve is given by κ.
- In linear algebra, the condition number of a matrix is given by κ.
- Kappa statistics such as Cohen's kappa and Fleiss' kappa are methods for calculating inter-rater reliability.
- Physics
- In cosmology, the Einstein gravitational constant is denoted by κ.
- In physics, the torsional constant of an oscillator is given by κ.
- In physics, the coupling coefficient in magnetostatics is represented by κ.
- In physics, the dielectric coefficient is represented by κ.
- In fluid dynamics, the von Kármán constant is represented by κ.
- In thermodynamics, the compressibility of a compound is given by κ.
- Engineering
- In structural engineering, κ is the ratio of the smaller factored moment to the larger factored moment and is used to calculate the critical elastic moment of an unbraced steel member.
- In electrical engineering, κ is the multiplication factor, a function of the R/X ratio of the equivalent power system network, which is used in calculating the peak short-circuit current of a system fault. κ is also used to denote conductivity, the reciprocal of resistivity, rho.
- Biology and biomedical science
- In biology, kappa and kappa prime are important nucleotide motifs for a tertiary interaction of group II introns.
- In biology, kappa designates a subtype of an antibody component.
- In pharmacology, kappa represents a type of opioid receptor.
- Psychology and psychiatry
- In psychology and psychiatry, kappa represents a measure of diagnostic reliability.
- Economics
- In macroeconomics, kappa represents the capital-utilization rate.[2]
Uppercase (Κ)
edit- History
- In textual criticism, the Byzantine text-type (from Κοινη, Koine, the common text).
- Mathematics and statistics
- In set theory, kappa is often used to denote an ordinal that is also a cardinal.
- Chemistry
- In chemistry, kappa is used to denote the denticity of the compound.
- In pulping, the kappa number represents the amount of an oxidizing agent required for bleaching a pulp.
Character encodings
editPreview | Κ | κ | ϰ | Ⲕ | ⲕ | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | GREEK CAPITAL LETTER KAPPA | GREEK SMALL LETTER KAPPA | GREEK KAPPA SYMBOL | COPTIC CAPITAL LETTER KAPA | COPTIC SMALL LETTER KAPA | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 922 | U+039A | 954 | U+03BA | 1008 | U+03F0 | 11412 | U+2C94 | 11413 | U+2C95 |
UTF-8 | 206 154 | CE 9A | 206 186 | CE BA | 207 176 | CF B0 | 226 178 148 | E2 B2 94 | 226 178 149 | E2 B2 95 |
Numeric character reference | Κ |
Κ |
κ |
κ |
ϰ |
ϰ |
Ⲕ |
Ⲕ |
ⲕ |
ⲕ |
Named character reference | Κ | κ | ϰ, ϰ | |||||||
DOS Greek | 137 | 89 | 161 | A1 | ||||||
DOS Greek-2 | 181 | B5 | 228 | E4 | ||||||
Windows 1253 | 202 | CA | 234 | EA | ||||||
TeX | \kappa |
- Mathematical Kappa
Preview | 𝚱 | 𝛋 | 𝛞 | 𝛫 | 𝜅 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL BOLD CAPITAL KAPPA |
MATHEMATICAL BOLD SMALL KAPPA |
MATHEMATICAL BOLD KAPPA SYMBOL |
MATHEMATICAL ITALIC CAPITAL KAPPA |
MATHEMATICAL ITALIC SMALL KAPPA | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 120497 | U+1D6B1 | 120523 | U+1D6CB | 120542 | U+1D6DE | 120555 | U+1D6EB | 120581 | U+1D705 |
UTF-8 | 240 157 154 177 | F0 9D 9A B1 | 240 157 155 139 | F0 9D 9B 8B | 240 157 155 158 | F0 9D 9B 9E | 240 157 155 171 | F0 9D 9B AB | 240 157 156 133 | F0 9D 9C 85 |
UTF-16 | 55349 57009 | D835 DEB1 | 55349 57035 | D835 DECB | 55349 57054 | D835 DEDE | 55349 57067 | D835 DEEB | 55349 57093 | D835 DF05 |
Numeric character reference | 𝚱 |
𝚱 |
𝛋 |
𝛋 |
𝛞 |
𝛞 |
𝛫 |
𝛫 |
𝜅 |
𝜅 |
Preview | 𝜘 | 𝜥 | 𝜿 | 𝝒 | 𝝟 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL ITALIC KAPPA SYMBOL |
MATHEMATICAL BOLD ITALIC CAPITAL KAPPA |
MATHEMATICAL BOLD ITALIC SMALL KAPPA |
MATHEMATICAL BOLD ITALIC KAPPA SYMBOL |
MATHEMATICAL SANS-SERIF BOLD CAPITAL KAPPA | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 120600 | U+1D718 | 120613 | U+1D725 | 120639 | U+1D73F | 120658 | U+1D752 | 120671 | U+1D75F |
UTF-8 | 240 157 156 152 | F0 9D 9C 98 | 240 157 156 165 | F0 9D 9C A5 | 240 157 156 191 | F0 9D 9C BF | 240 157 157 146 | F0 9D 9D 92 | 240 157 157 159 | F0 9D 9D 9F |
UTF-16 | 55349 57112 | D835 DF18 | 55349 57125 | D835 DF25 | 55349 57151 | D835 DF3F | 55349 57170 | D835 DF52 | 55349 57183 | D835 DF5F |
Numeric character reference | 𝜘 |
𝜘 |
𝜥 |
𝜥 |
𝜿 |
𝜿 |
𝝒 |
𝝒 |
𝝟 |
𝝟 |
Preview | 𝝹 | 𝞌 | 𝞙 | 𝞳 | 𝟆 | |||||
---|---|---|---|---|---|---|---|---|---|---|
Unicode name | MATHEMATICAL SANS-SERIF BOLD SMALL KAPPA |
MATHEMATICAL SANS-SERIF BOLD KAPPA SYMBOL |
MATHEMATICAL SANS-SERIF BOLD ITALIC CAPITAL KAPPA |
MATHEMATICAL SANS-SERIF BOLD ITALIC SMALL KAPPA |
MATHEMATICAL SANS-SERIF BOLD ITALIC KAPPA SYMBOL | |||||
Encodings | decimal | hex | dec | hex | dec | hex | dec | hex | dec | hex |
Unicode | 120697 | U+1D779 | 120716 | U+1D78C | 120729 | U+1D799 | 120755 | U+1D7B3 | 120774 | U+1D7C6 |
UTF-8 | 240 157 157 185 | F0 9D 9D B9 | 240 157 158 140 | F0 9D 9E 8C | 240 157 158 153 | F0 9D 9E 99 | 240 157 158 179 | F0 9D 9E B3 | 240 157 159 134 | F0 9D 9F 86 |
UTF-16 | 55349 57209 | D835 DF79 | 55349 57228 | D835 DF8C | 55349 57241 | D835 DF99 | 55349 57267 | D835 DFB3 | 55349 57286 | D835 DFC6 |
Numeric character reference | 𝝹 |
𝝹 |
𝞌 |
𝞌 |
𝞙 |
𝞙 |
𝞳 |
𝞳 |
𝟆 |
𝟆 |
These characters are used only as mathematical symbols. Stylized Greek text should be encoded using the normal Greek letters, with markup and formatting to indicate text style.
References
edit- ^ "kappa". Oxford English Dictionary (Online ed.). Oxford University Press. (Subscription or participating institution membership required.)
- ^ "University of Hong Kong School of Business" (PDF). HKU.